This invention relates generally to manufacturing, and particularly to the fixtures that are used to hold parts while they are machined by equipment such as CNC (“computer numerical control”) equipment in a machining center.
One conventional fixture that is commonly used to hold small metal parts during machining has hydraulic clamp arms that hold a number of parts to a fixture. After the parts to be machined are loaded onto the fixture, an operator connects a hydraulic line to a fitting on the fixture and opens a hydraulic source, energizing the clamp arms so that they hold the parts in place. The hydraulic line is then removed, and the fixture enters a work area where the parts are machined by the CNC equipment. After the machining is completed, the fixture is pulled from the work area, the hydraulic line is reconnected, the hydraulic pressure is released through the line, and the parts are removed from the fixture. The process is then repeated for the next batch of parts.
There are several potential problems with this kind of system. First, connecting, disconnecting, and reconnecting the hydraulic line leads to wear of the fitting. In addition to wear, the fitting can become damaged by exposure to coolant or machining chips, or by operator mishandling. Second, operators may forget or fail to connect or energize the hydraulic line, or forget or fail to remove the hydraulic line before the fixture enters the work area. These mistakes can lead to costly machine damage or a system crash.